Obama administration was 'impotent' about South China Sea: Donald Trump

US President Donald Trump Wednesday slammed his predecessor Barack Obama for being "impotent" and not stopping China from expanding its influence in the South China Sea, saying the Chinese Navy was now posing a confrontational challenge for America in the disputed region.

President Trump's remarks came hours after he was briefed at the White House by Secretary of State Mike Pompeo on his meetings with the top Chinese leadership in Beijing this week.

"The Obama administration was impotent about the South China Sea," Trump said during an interaction with reporters Abroad Air Force One.

He said the Chinese Navy was now posing a confrontational challenge for America in the disputed region.

China is engaged in hotly contested territorial disputes in the South China Sea, and with Japan in the East China Sea. Both the areas are stated to be rich in minerals, oil and other natural resources. They are also vital to global trade.

China claims almost all of the South China Sea. Vietnam, the Philippines, Malaysia, Brunei and Taiwan have counter claims over the area.

The US has been conducting regular patrols in the South China Sea to assert freedom of navigation in the area where Beijing has built up and militarised many of the islands and reefs it controls in the region.

During Pompeo's trip, Trump earlier told reporters at the White House that China was sending a message to him, but those messages did not work.

He said Pompeo was treated him great respect during his trip to Beijing.

"They're just trying to get me a message. But those messages don't work. They don't work. But no, I think they treated him with great respect, actually. You know, they had meetings besides just the news conference. And I think they treated him with great respect," he said when asked if he was concerned the way the Chinese treated Pompeo.

Trump also said Pompeo did not have a great meeting in China.

"It wasn't so much - I guess he was giving them a message, and they were giving him a message to come back to me," Trump said.

However, State Department Spokesperson Heather Nauert told reporters at a news briefing that Pompeo had a good, constructive meetings with his Chinese counterparts.

"They're certainly a competitor. It's a complex and broad-based relationship that we have with China, as you all saw in the comments and exchanges between the Secretary and his counterparts. We have areas of common interest. North Korea is one of them," Nauert said.

"Working to combat illegal narcotics is another area where we work well together. We also have areas of disagreement and areas where we have challenges, and we'll keep working together on that. It's obviously an important relationship that we need to work hard to maintain," she said.